feat: add simple jwt middleware and update oauth handlers

backend/internal/auth/jwt.go

@@ -0,0 +1,60 @@
+package auth
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"gitea.d3m0k1d.ru/d3m0k1d/d3m0k1d.ru/backend/internal/storage"
+	"github.com/gin-gonic/gin"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+var jwtSecret = []byte(os.Getenv("JWT_SECRET"))
+
+func GenerateJWT(user storage.User) (string, error) {
+	token := jwt.NewWithClaims(jwt.SigningMethodHS512, jwt.MapClaims{
+		"id":    user.ID,
+		"email": user.Email,
+		"login": user.GithubLogin,
+	})
+	tokenString, err := token.SignedString(jwtSecret)
+	if err != nil {
+		return "", err
+	}
+	return tokenString, nil
+}
+
+func JWTMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		auth := c.GetHeader("Authorization")
+		if !strings.HasPrefix(auth, "Bearer ") {
+			c.AbortWithStatusJSON(401, gin.H{"error": "Bearer required"})
+			return
+		}
+
+		tokenString := strings.TrimPrefix(auth, "Bearer ")
+		token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+
+			if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+				return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
+			}
+			return jwtSecret, nil
+		})
+
+		if err != nil || !token.Valid {
+			c.AbortWithStatusJSON(401, gin.H{"error": "invalid token"})
+			return
+		}
+
+		claims, ok := token.Claims.(jwt.MapClaims)
+		if !ok {
+			c.AbortWithStatusJSON(401, gin.H{"error": "invalid claims"})
+			return
+		}
+
+		c.Set("user_id", int(claims["id"].(float64)))
+		c.Set("login", claims["login"].(string))
+		c.Next()
+	}
+}